Typically grate plates are used in apparatus which handle bulk particulate material, cement clinker or other mineral materials which have passed through a kiln. Examples of similar apparatus and the grate plates of the prior art may by seen in U. S. Pat. Nos. 4,762,489; 4,870,913; and 5,282,741. Grate plates are attached to carrier or support beams by T-bolts or clamps such that they may be easily detached from the beams as needed for replacement by new plates. The grate made up of such plates and beams may be a combination of stationary and moving elements, a traveling grate cooler, a thrust grate cooler and the like. The material, hereinafter referred to by way of example as clinker, is deposited on the grate and distributed thereon as well as possible in a bed or layer. As is well known cooling air from a remote source is supplied to the underside of the grate plates and passes through openings in the plate, thereafter migrating upwardly through the bed to effect cooling of the clinker. Those familiar with the art of cooling a clinker are aware that it may be advantageous, and is in fact sometimes necessary to control the air flow across the width of the grate, providing more or less air flow in certain areas. A significant problem associated with the inability of known grate designs to properly distribute the air is the occurrence of streams of an uncooled clinker over regions of the grate. This problem is potentially exacerbated by the tendency of the cooling air to be discharged upwardly from the grate plate, thereby diminishing the lateral cooling effect on contiguous portions of the clinker bed.